Electromagnetic vibratory pump



Jan. 30, 1962 c. SCHINDLER 3,013,735

ELECTROMAGNETIC VIBRATORY PUMP Filed June 17, 1959 2 Sheets-Sheet 1 INVENTOR. Carl Schinaer Jan. 30, 1962 c. SCHINDLER ELECTROMAGNETIC VIBRATORY PUMP 2 Sheets-Sheet 2 Filed June 17, 1959 INVENTOR. Carl ficfimzZer BY Pia 3,018,735 ELECTROMAGNETIC VIBRATORY PUMP Carl Schindler, Wauwatosa, Wis., assignor to McGraw- Edison Company, Milwaukee, Wis., a corporation of Delaware Filed June 17, 1959, Ser. No. 821,027 7 Claims. (Cl. 10353) This invention relates to alternating current electromagnetic vibratory pumps.

Alternating current electromagnetic pumps are known wherein an armature suspended magnetically within a pole structure vibrates in accordance with the cyclic variations in alternating current energizing a winding linked with the pole structure, and a pumping piston rigid with the armature executes rapid vibrations within a pumping chamber to continuously supply fluid under pressure. Such vibratory electromagnetic pumps are also known wherein the armature is magnetically suspended in a mean position determined by the magnitude of the magnetic flux in the pole structure, and valve means operatively connected to the armature selectively controls the direc tion of energy delivery from the pump in accordance with the mean position of the armature. Such a vibratory electromagnetic pump arranged to selectively control direction of energy delivery is particularly suited for voltage regulating apparatus in that it not only supplies fluid under pressure for operating a work cylinder which may in turn actuate a voltage regulating device such as a tap changer, but it is also adapted to selectively direct fluid from the pump into either end of the work cylinder in accordance with variations in the voltage above and below a predetermined value to thus control the regulating device in accordance with the magnitude of the voltage. One disadvantage of such electromagnetic vibratory pump, however, is that the pump does not always start after the apparatus has stood idle. The liquid in which the pump is immersed evolves air or gas incident to cooling and reduction in pressure which may accumulate in the pumping chamber, and the excursions of the pumping piston within ited States Patent the gas-filled pumping chamber may not be of sufiicient I amplitude to start the pump.

It is an object of the invention to provide an electromagnetic vibratory pump which will always start pumping regardless of how long it has been idle.

This and other objects and advantages of the invention will be more apparent from the following description when taken in conjunction with the accompanying drawing wherein:

FIG. 1 is a vertical section view through an electromagnetic pump embodying the invention;

FIG. 2 is a front elevation view of the embodiment of FIG. 1;

FIG. 3 is an enlargement of a portion of FIG. 1;

FIG. 4 is an enlarged view of the pumping piston; and

FIG. 5 is an enlarged view of the pumping chamber.

Referring to the drawing, it will be seen that the alternating current electromagnetic pump immersed in oil or other suitable liquid comprises a housing, or body portion, 10 of suitable magnetic material such as steel having a vertically upward extending, generally cylindrical bore 11 adapted to receive an energizing winding 12 wound on an insulating spool 14. Spool 14 is disposed against a spacer 15 -of suitable magnetic material such as steel which rests upon a coil support 16 preferably of a nonmagnetic metallic material such as bronze. A suitable mounting plate 17 and the coil support 16 are secured to the housing 10 by screws 18 threaded into tapped holes within housing 10.

The walls of housing 10 surrounding spool 14 together with spacer 15 comprise a magnetic field structure, or pole structure. An armature, or plunger 20, of suitablem'ag- 3,l8,735 Patented Jan. 30, 1 962 netic material such as steel is magnetically suspended within the electromagnetic pole structure when winding 12 is energized. The armature 20 executes rapid vibrations of small amplitude due to the cyclic variations of the magnetic flux in the pole structure when an alternating current voltage is impressed on energizing winding 12. Plunger '20 is axially bored to receive a plunger rod pumping piston 21 which is rigid with plunger 20 and reciprocates axially within a vertical aperture, or cylinder, 24 in body portion 10. A valve rod 26 re'ciprocable within the upper portion of cylinder 24 is resiliently connected to plunger 20 and occupies different axial positions depending upon the magnitude of the voltage impressed on energizing winding 12 as explained hereinafter. Opposed piston rods, i.e., plunger rod 21 and valve rod 26, define a pumping chamber 23 within cylinder 24. As illustrated in the drawing cylinder 24 may be formed in a sleeve bushing 25 pressed into housing 10.

The lower end of plunger rod 21 is aflixed to the midportion of a plurality of superimposed, thin, flexible leaf springs 27 which are secured at their ends to vertical rods 28 disposed outward from housing 10. Rods 28 at their upper ends are secured to a cross bar 30 which together with rods 28 constitutes a weight of sufiicient mass to prevent vibration of valve rod 26 due to the cyclic variations of magnetic flux in the pole structure. The leaf springs 27 provide a flexible resilient connection between valve rod 26 and plunger 20 permitting the plunger 2% and plunger rod 21 to resonate in accordance with the cyclic periodicity of the alternating current about a mean position determined by the magnitude of the magnetic flux in the pole structure while the mass of weight 30 is suflicient so that valve rod 26 will not vibrate and remains substantially stationary.

Valve rod 26 within cylinder 24 extends through a clearance aperture in crossbar 30 and is secured to a ball 31 disposed within a recess 32 in crossbar 3t and held therein by suitable retaining means 33 to provide a universal connection between crossbar 36 and valve rod 26 and thus prevent binding of valve rod 26 within cylinder 24. Valve rod 26, crossbar 39, rods 28, plunger 20, springs 27, and plunger rod 21 constitute a magnetically suspended assembly when winding 12 is energized and which rises and falls with variations in the magnitude of the voltage. This assembly occupies a mean, or neutral, position when the voltage is a predetermined value and also has positions on opposite sides of this neutral position and varies its position in accordance with the magnitude of the voltage impressed on winding 12. Plunger 20 and plunger rod 21 continue to execute minute but rapid vibrations and to pump fluid while the assembly is magnetically suspended and remains substantially stationary in the neutral position and in positions on opposite sides of the neutral position. The stroke of plunger rod 21 is minute but the strokes occur in sufliciently rapid succession so that an ample supply of fluid can be pumped at adequate pressure to operate a suitable motor means.

Fluid is delivered from pumping chamber 23 through an outlet passage in housing 10 including a first horizontal portion 34 registering with cylinder 24 between plunger rod 21 and valve rod 26, a vertical portion 35 in housing 10, and a horizontal portion 36 also registering with cylinder 24. Housing 10 has delivery passages 37 and 38 registering with cylinder 24 above and below horizontal portion 36 of the outlet passage. An outlet, or check, valve 39 normally closes the outlet passage 34- 3536. When the assembly is magnetically suspended above the neutral position due to an increase in voltage above the nominal value, an increased diameter portion, or valve, 40 on rod 26 directs fluid into delivery passage 38 connected to one end of a work cylinder 41 which may be utilized to actuate a tap changer or other voltage regulating apparatus. Fluid from the opposite end of the work cylinder 41 is returned through delivery passage 37 and is directed by an increased diameter portion, or valve, 42 on rod 26 into an exhaust passage 43. Similarly when the magnetically suspended assembly assumes a position on the opposite side of the neutral position due to a decrease in voltage below the nominal value, valve 40 prevents flow of fluid into delivery passage 38 and directs the fluid from the pump into delivery passage 37 connected to the opposite end of the work cylinder 41. Fluid is returned through delivery passage 38 and is directed by increased diameter portion, or valve, 44 on rod 26 into an exhaust passage 45 from whence it returns into the fluid in which the pump is immersed. When the assembly is at the mean, or neutral, position, valve 40 is symmetrically disposed relative to outlet passage 34 35-36, and thus the piston 48 of the work cylinder 41 remains stationary and no tap change occurs.

Work cylinder piston 48 initially assumes a central position within Work cylinder 41 corresponding to the predetermined, or nominal, value of the voltage impressed on energizing winding 12, and the work cylinder piston 48 is displaced to positions on opposite sides of this central position in accordance with variations in the voltage above and below the nominal value. Displacement of piston 48 is converted by rack-and-pinion means (not shown) within work cylinder 48 into rotation of an output shaft 70. My copending application Ser. No. 820,965 entitled Self-Regulating Transformer and having the same assignee as the subject invention discloses and claims self-adjusting feedback means between the output shaft 70 and the voltage sensing means to compensate the voltage sensing means for movement of the output shaft 70 and thus permit the work cylinder piston 48 and output shaft 70 to assume a null, or neutral, position at any voltage between the upper and lower bandwidth limits. The work cylinder piston 48 is thus moved in a direction to accomplish a tap change but is brought to rest at a neutral position by the compensating means and no tap change occurs until the voltage actually departs beyond the bandwidth limits. The compensating means thus eliminates hunting and permits the voltage regulating apparatus to integrate departures of voltage from the nominal value with respect to both time and the magnitude of the voltage departure from the nominal value.

The compensating means will not be illustrated and described in detail. Within the voltage bandwidth the work cylinder piston 41 and output shaft 70 are actuated in a direction to effect a tap change and in proportion to the departure of voltage from the nominal value, and the feedback means returns the voltage sensing means including valve 40 to a neutral position wherein the forces on one end of the work cylinder piston 48 resulting from pumping liquid past valve 40 into one end of the work cylinder is equal to, but opposite from, the force resulting from resilient means (not shown) tending to return the work cylinder piston 48. The compensating feedback means includes a compensating screw 72 operatively connected to output shaft 70 for rotation therewith, a compensating bar 73 threadably engaging the compensating screw 72 and adapted to be raised or lowered in accordance with the direction of rotation of the output shaft 70, a bracket 74 rigidly held at one end and pivotally mounted intermediate its ends on compensating bar 73, and cempensating springs 75 secured at their lower end to the free end of bracket 74 and at their upper ends to a support member 76 affixed by screws 77 to the cross bar 30 of the magnetically suspended assembly. The compensating springs 75 normally exert a downward force on the magnetically suspended assembly opposed to the upward force resulting from the magnetic flux in the pole structure. Rotation of compensating screw 72 varies the height of compensating bar 73 and tilts bracket 74 in a direction to increase or decrease the tension in compensating springs 75 and thus return the magnetical- 1y suspended assembly including valve 40, to a null position wherein the hydraulic force from the electromagnetic pump exerted against one end of work cylinder piston 48 is equal to but opposite from the force exerted by the aforementioned spring means tending to return the work cylinder piston 48 in the opposite direction. Consequently, the work cylinder piston 48 and output shaft 70 come to rest at a null position displaced from the initial position by an amount proportional to the magnitude of the voltage departure from the nominal value, and each position of work cylinder piston 48 within work cylinder 41 corresponds to a predetermined voltage impressed on energizing winding 12.

It will be appreciated that pumping piston rod 21 and rod valve 26 are both part of the magnetically suspended assembly and are thus raised and lowered together and that consequently the output of the vibratory pump is substantially constant. Outlet valve 39 includes a sleeve bushing 46 within a horizontal aperture in housing 10 and registering with cylinder 24 adjacent the pumping chamber 23. Bushing 46 is axially bored to define the horizontal portion 34 of the outlet passage and to provide a reduced diameter valve seat against which a ball valve 47 is held by a helical spring 49. Spring 49 surrounds a support pin 50 aflixed to a cover plate 51 which is secured by screws to housing 10 and partially defines the vertical portion 35 of the outlet passage.

The lower end of cylinder 24 communicates with a conical, downwardly flaring opening 52 in sleeve bushing 25 which registers with a horizontally extending aperture 53 in body portion 10. The upper end of plunger rod 21 within cylinder 24 is tubular and provides an axial opening 54 which constitutes the inlet passage to the pumping chamber 23. The upper tip of plunger rod 21 forms a valve seat for receiving an inlet ball valve 56 preferably of suitable material having exceptionally high wearing qualities such as polytetrofluorethylene. A Wire loop 57 secured to inlet ball valve 56 fits within axial opening 54 in plunger rod 21 and is secured to one end of a valve spring 58 within axial opening 54. The other end of valve spring 58 is secured to a wire 60 extending through a transverse hole in plunger rod 21 registering with axial opening 54. A transverse inlet aperture 61 registering with axial opening 54 is also provided in the wall of plunger rod 21. Cylinder 24 communicates with horizontal opening 53 extending through body portion 10 so that opening 53, in effect, constitutes an extension of inlet aperture 61 and places axial opening 54 in plunger rod 21 in communication with the liquid in which the pump is immersed. In operation of the electromagnetic vibratory pump, inlet ball valve 56 is forced against its seat at the tip of plunger rod 21 on the upstroke of plunger 20, thereby forcing fluid under pressure out through outlet valve 39 and through the outlet passage 34-3536, from whence it is directed by valve 40 into delivery passage 37 or 38 depending upon the position assumed by the magnetically suspended assembly relative to the neutral position. On the downstroke of plunger rod 21, outlet valve 39 closes a partial vacuum is created in pumping chamber 23, thereby lifting inlet ball valve 56 off its seat and forcing liquid into pumping chamber 23. On the next upstroke of plunger 20, inlet ball valve 56 is again forced against its seat as plunger rod 21 advances toward rod valve 26, thereby forcing open outlet valve 39 and delivering fluid under pressure through outlet passage 34-35-36 from whence it is directed by valve 40 into one of the delivery passages 37 or 38.

Preferably the axial height of pumping chamber 23, determined by the separation between plunger rod 21 and rod valve 26, is not more than several times the amplitude of vibration, or stroke, of plunger rod 21. As explained hereinbefore, the electromagnetic vibratory pump is immersed in a fluid which may evolve gas incident to cooling and pressure drop. This gas occasionally accumulated in the pumping chamber of prior art electromagnetic pumps and prevented the pump from starting after the apparatus was idle. Regardless of the amount of air or gas accumulated within pumping chamber 23, the downward movement of plunger 20 lifts inlet ball valve 56 ofif its seat due to a partial vacuum within pumping chamber and also forces liquid to fiow through inlet aperture 61 and axial opening 54 into pumping chamber 23. The electromagnetic pump is thus self-priming regardless of the length of time the apparatus has been idle.

While only a single embodiment of the invention has been illustrated and described, many modifications and variations thereof will be apparent to those skilled in the art, and consequently it is intended in the appended claims to cover all such modifications and variations as fall within the true spirit and scope of the invention.

I claim:

1. In an alternating current electromagnetic vibratory pump adapted to be immersed in a liquid and having a body portion defining a pumping chamber, said body portion having first and second passages registering with said pumping chamber, an outlet valve in said first passage, a pumping piston reciprocable within said second passage and extending into said pumping chamber, said electromagnetic pump including a pole structure, an energizing winding on said pole structure, and an armature connected to said piston and adapted for magnetic suspension within said pole structure and arranged to vibrate in response to fluctuations of the magnetic flux in said pole structure incident to a source of alternating current being impressed on said energizing winding for rapidly vibrating said pumping piston to thereby force fluid under pressure out of said first passage, said pumping piston having an axial opening constituting the inlet passage to said pumping chamber and also having an inlet aperture registering with said axial opening and in continuous communication with the liquid in which the pump is immersed, said piston also having a valve seat at the end of said axial opening within said pumping chamber, a valve disposed against said valve seat, and means within said axial opening for resiliently holding said valve against said valve seat, whereby said pump is self-priming even if gas evolved by said liquid accumulates within said pumping chamber when said pump is idle.

2. In an alternating current electromagnetic vibratory pump including a field structure, an energizing winding on said field structure, a body portion rigid with said field structure and defining a pumping chamber, an armature magnetically suspended within said field structure arranged to vibrate due to the cyclic variations of the alternating current impressed on said energizing winding, and a pumping piston rigid with said armature and arranged to vibrate cyclically within said pumping chamber, the improvement comprising said pumping piston having in the end thereof within said pumping chamber an axial bore constituting the inlet passage to said pumping chamber and a valve seat at the end of said axial bore, said piston also having an inlet aperture exterior of said body portion registering with said axial bore and in continuous communication with the liquid in which said pump is immersed, and a check valve on said pumping piston disposed against said valve seat and adapted to close said axial bore when said pumping piston is moved in a direction into said pumping chamber and to open when said pumping piston is moved in a direction out of said pumping chamber, and means for resiliently urging said check valve against said valve seat, whereby said pump is selfpriming even if gas evolved by said liquid accumulates within said pumping chamber when said pump is idle.

3. In an alternating current electromagnetic vibratory pump in accordance with claim 2 wherein the volume of said pumping chamber is no greater than several times the volume of liquid displaced by said piston in one stroke thereof.

4. A vibratory alternating current electromagnetic 6 pump including a pole structure, an energizing winding on said pole structure, a body portion rigid with said pole structure and having a cylindrical opening defining a pumping chamber, said body portion also having an outlet passage registering with said pumping chamber, a check valve normally closing said outlet passage, an armature suspended magnetically from said pole structure, a piston rod rigid with said armature adapted to reciprocate within said cylindrical opening, said armature being arranged to vibrate due to the cyclic variations in the alternating current impressed on said energizing winding and to advance said piston rod into and withdraw it from said pumping chamber whereby liquid in said pumping chamber is forced out through said check valve, said piston rod having at the end thereof within said cylindrical opening an axial opening defining the inlet passage to said pumping chamber and also having an inlet aperture exterior of said body portion registering with said axial opening, said piston rod also carrying a check valve adapted to close said opening when said piston rod is moved in a direction into said pumping chamber and to open when said piston rod is moved in a direction out of said pumping chamber, the axial dimension of said pumping chamber being no greater than several times the stroke of said piston rod.

5. A vibratory alternating current electromagnetic pump including an electromagnetic field structure, an energizing winding on said field structure, a body portion rigid with said field structure and having a cylinder provided with an outlet passage and also having a pair of delivery passages, a check valve in said outlet passage, an armature suspended magnetically from said field structure, a pumping piston rod within said cylinder rigid with said armature, a valve rod within said cylinder, means for resiliently connecting said valve rod to said armature, said piston rod and said valve rod within said cylinder being spaced above and below said outlet passage and defining a pump chamber therebetween, said piston rod at the end within said cylinder having an axial bore constituting the inlet passage to said pumping chamber and an inlet aperture registering with said bore exterior of said body portion, a check valve carried by said piston rod adapted to close said axial bore when said piston rod is moved in a direction into said cylinder, said armature, said valve rod, and said piston rod constituting an assembly adapted to occupy a mean position determined by the alternating current voltage impressed on said winding and said armature and said piston rod being arranged to vibrate about said mean position due to the cyclic variations in the alternating current, a weight rigid with said valve rod and having sufiicient mass to prevent said valve rod from vibrating, said valve rod selectively connecting said delivery passages with said outlet passage in accordance with said mean position.

6. An alternating current vibratory electromagnetic pump comprising a body portion including a pole structure, an energizing winding on said pole structure, an armature suspended magnetically within said pole structure in a mean position determined by the magnitude of magnetic flux in said pole structure incident to an alternating current voltage being impressed on said Winding and being arranged to vibrate about said means position due to the cyclic variations in said magnetic flux, said body portion having a vertical cylinder therein and an outlet passage registering with said cylinder and also having delivery passages, opposed piston rods within said cylinder the first of which is rigid with said armature and the second of which is yielding connected to said armature, said opposed piston rods defining therebetween a pumping chamber registering with said outlet passage, said first piston rod having at the end within said cylinder an axial opening constituting the inlet passage to said pumping chamber and an inlet aperture registering with said axial opening exterior of said body portion, an inlet valve carried by said first piston rod adapted to close said axial opening when said first piston rod is moved in a direction into said cylinder and to open when said first piston rod is moved in a direction out of said cylinder, a weight connected to said second piston rod having sufiicient mass to prevent vibration thereof due to the cyclic vibrations of said armature, said second piston rod varying its position in accordance with said mean position of said armature and carrying valve means for selectively connecting said delivery passages with said outlet passage in accordance with said mean position.

7. An alternating current electromagnetic pump comprising a body portion including a pole structure, an energizing winding on said pole structure, said body portion having a vertical cylinder therein and an outlet passage registering said cylinder and also having delivery passages registering with said cylinder, an outlet valve in said outlet passage, opposed first and second piston rods within said cylinder spaced above and below said outlet passage and defining a pumping chamber therebetween, an armature rigid with the first of said piston rods magnetically suspended within said pole structure and adapted to vibrate in accordance with the cyclic pulsations in the magnetic flux in said pole structure resulting from an alternating current voltage impressed on said energizing winding, said first piston rod having an axial opening in the end within said cylinder defining the inlet passage to said pumping chamber and an inlet aperture exterior of said body portion registering with said axial opening, an inlet valve carried by said first piston rod adapted to close said axial opening when said first piston rod is moved in a direction into said cylinder and to open when said first piston rod is moved in the opposite direction, resilient means for connecting said second piston rod and said armature, a weight connected to said second piston rod, said first and second piston rods, said armature, and said weight constituting an assembly adapted to occupy a mean position determined by the voltage impressed on said winding, said weight having sufiicient mass to prevent said second piston rod from vibrating, the end of said outlet passage remote from said pumping chamber registering with said cylinder between said .delivery passages, said second piston rod carrying valve means adapted to selectively direct the fluid from said outlet passage into said delivery passages in accordance with said mean position, said opposed pistons being spaced apart, when said winding is de-cnergized, a distance not more than several times the stroke of said first piston rod.

References Cited in the file of this patent UNITED STATES PATENTS 458,873 Van Depoele Sept. 1, 1891 1,293,936 Rose Feb. 11, 1919 1,790,547 La Pointe Jan. 27, 1931 2,722,891 Weinfurt Nov. 8, 1955 

